Currently, up to four radio systems are required to implement traffic collision avoidance system (TCAS), air traffic control (ATC) transponder, distance-measuring equipment (DME), and universal access transceiver (UAT) avionics functions on an aircraft. This would require four different transceivers. This implementation is not optimal in terms of weight, cost, volume, and power consumption.
Some systems have attempted to resolve this problem. In one current embodiment of an L-band receiver system, a DME receiver is included along with a receiver for the TCAS, transponder, and UAT. This prior-art design still includes all the analog circuitry for generating three separate narrowband signals for the TCAS, transponder, and UAT intermediate frequency (IF) outputs. The DME IF output is separately generated.